Pothead for insulated conductors



Dec. '30, 1930. A. o. AUSTIN 1,786,729 POTHEAD FOR INSULATED C-ONDUCTORSFiled Jan. 16, 19 25 as ix I0 INVENTOR 11 m 9 t A TTORNEYS Patented Dec.30, 1930 UNITED" STATES PATENT, OFFICE ARTHUR O. AUSTIN, OF BABBERTON',OHIO, ASSIGNOR, BY MESNE ASSIGNMENTS, TO THE'OHIO BRASS COMPANY, OFMANSFIELD, OHIO, A CORPORATION OF NEW JERSEY PO'IHItlAD FOB INSULATEDCONDUCTOBS Application filed January 1a, 1925. Serial no. 2,754.

This invention relates to outlet housings commonly known as potheadssuch as are 'used for the transition of a conductor from an insulatedcable to a bus bar or overhead 5. support, and has for its object theprovision of a device of the class named in which the exposed portion ofthe insulating material will be rotected'fromthe atmosphere and suppliedwith an insulatingliquid or compound and in which flash-over between theconductor and its sheath or other grounded objects will be prevented. I

The invention is exemplified in the combination and arrangements ofparts shown in the-accompanying drawing and described in the followingspecifications and it is more particularly pointed out in the appendedclaims. i

In the drawing-- Thefigure is an elevation of a pothead constructionshowing one embodiment of the prese' t invention, parts of the devicebeing sho in vertical section. f

The numeral designates aconductor thereto, the outer surface of thewinding being covered by a sheath 12 of lead or other suitable material.The insulation 11 is commonly made up of narrow strips of papersaturated with oil or other insulating compound and wound in layers uponthe conductor 10. The outer sheath 12 protects the insulating materialand prevents the escape of the insulating liquid with which the materialis saturated. .It'will be apparent that at the termination of the sheath12 and the insulating material 11, it will be necessary to make someprovision ,to'protectthe insulating material so as to retain theinsulating fluid and prevent entrance of moisture. It will also, beapparent that there will be a concentration of electrostatic lines offorce atthe termination of the sheath which would give rise to dischargefrom the conductor to the sheath unless some provision is made toprovide sutficient insulation at this point. In the construction shownin the drawing for taking care of these conditions, a metal tubu larhousing or bell '13 is provided which is tapered inwardly at its lowerend to fit closecable having an insulated winding llvapplied' 10 andinsulation 11 pass through the opening-in'the lower end of the housingbut the sheath 12 is terminated adjacent the end of the housing and isflared outwardly as shown at 14 to provide a circumferential flange. Thelockmg collar 15 surrounds the sheath 12 below the flange 14 and isprovided with a flange 16 which grips thetflange 14 against the lowerend off the housin 13. A gasket 16 is interposed between the housing andthe flange 14 to provide a tight joint between the housing and thesheath 12.

Atthe' upper end of the housing 13, there is provided a supportingflange 17 having a gasket 18 thereon, and a ring 19 is secured to theflange 1-7 on top of the gasket 18 by bolts 20. A tubulardlelectrio'member 21 is secured to the interior of the ring'19 by oement22 or other suitable means so that when the ring 19 is securely fastenedtothe flange 17 the parts 13 and21 are united at their adjacent. ends toform a continuous casing. The ring 19 may be provided with a boss 23having a 0011(11111324: extending therethru to 1y about thev insulation11. The conductor permit the'interior of the casmg to be supplied withan insulating oil or compound.

The conduit 24.- may be closed by a p ug 25. A reservoir 26 may beprovided at the upper end of the housing member 21 for containing areserve supply of insulating liquid, and'a gauge glassf2Z is providedfor indicati the height of liquid in the reservoir 26. emperaturechanges will vary the amount of the insulating liquid held by thecovering 11 for the conductor 10. During warm weather, the insulatingliquid will expand and some of it will be forced from the interior ofthe sheath 12. At lower temperatures, the liquid will contract so thatan additional amount will enter the end of the cable. 'For this reason,

it is advisable to supply a considerable body .at the same time protectsthe covering for thezeonductor from exposure to the atmosphere. Themetallic member 13 diverges the flaring pothead 13 to the flange 17which is spaced outwardly a considerable distance from the conductor.The insulating member 28 extends between the covering 11 and the casingmember 13 to a point closely adjacent 15 the lower end of the casingmember. The

wall of the insulating member beingtapered at its lower end to permitthe end to extend well down into the tapered opening between theinsulating covering 11 and the member 13. The tubular member 29 isconcentric with the member 28 and is spaced outwardly therefrom andsecured thereto by rings of cementing material 31. The tubular member 30is likewise secured to the outer face of the 5 member 29 by cement 32.The entire series of tubular dielectric members is supported from thehousing member 13 by a cement zone 33 which connects the outer surfaceof the tubular member 30 with the inner sur- 30 face of the casingmember 13 near the top of this member. A flux control screen 34.

consisting of a sheet metal sleeve surround-- ing tubular member 13 maybe supported between the tubular member and the lower 35 edge of thehousing member 21 by having its 0 lower edge embedded in the cement 33.In

order to provide anadditional supply of insulating liquid, it maysometimes be advisable to use a supplemental supply reservoir 35whichmay be connected by a pipe 36 to the interior of the housing member13. A valve 37 is provided to control the supply of liquid through thepipe 36. The upper end of the conductor 10 1s connected to a conductorrod 38 which extends ,upwardly through the reservoir 26 and isconnectedat its upper end with conductors 39 and 40. A spring washer 41 may beinterposed between the clamp 42 for the conductor 39 and the stuflingbox43 at the upper end of the rod 38, within-the pothead and compensatesfor unequal expansion and contraction between the conductor and thecasing due to temperature changes.

' I claimp 1. The combination with a conductor hai inga dielectriccovering and an outer metal sheath, of a pothead for said conductorcomprising an inverted metallic bell having an opening through its lowerend for receiving said conductor, means for securing said sheath to saidbell adjacent said opening,

resilient means for supporting the portionof said conductor within saidpothead and a tubular dielectric member surrounding said Moreover aseries of conductor within said pothead and supported on said bell.

2. The combination with a conductor of a pothead therefor, a reservoirfor insulating compound supported by said pothead and resilient meansfor supporting the portion of said conductor in said pothead.

3. The combination with a conductor having a covering of dielectricmaterial and an outer metal sheath, of a pothead for said conductorcomprising a lower metallic bell and an upper dielectric casing member,a reservoir supported on said dielectric casing member and communicatingwith the interior thereof, means extending through said reser voir forsupporting the portion of said conductor within said pothead and aresilient member supported by said reservoir for sustaining saidconductor supporting means.

4. The combination with a conductor having a covering of dielectricmaterial and an outer metal sheath, of a pothead for said conductorcomprising an inverted flaring metallic bell having an opening throughits lower end for receiving said conductor, means for forming a tightjoint between said sheath and said bell adjacent the lower end of saidbell, a series of concentric tubular insulating members surrounding saidconductor within said bell and supported on said bell, a di electriccasing member connected with the upper end of said bell to form a closedhousing therewith, a reservoir for insulating compound communicatingwith the upper end of said dielectric casing member, a connectorextending through said reservoir and secured to said conductor and meansfor supporting said connector to said reservoir.

5. In combination, a conductor having an insulating covering and anouter metal sheath, and a terminal housing for said conductor comprisinga metallic casin member having an opening at one end rough which saidconductor and covering extend into said casing member, said casingmember being flared outwardly away from said covering, a complementarycasing member of dielectric material having one end thereof arranged inregistration with the upper end of said metallic casing member, meansfor securing the registering ends of said casing members together, a capsupported on the upper end of said dielectric casing member and providedwith a terminal for said conductor, and a porcelain tube disposed withinsaid casing members and overlappin the joint between the connected endsof sai casin being tapered and extending into the tapered openingbetween'said metallic casing member and. said insulating covering.

6. In combination a conductor having a covering of dielectric material,a liquid tight casing of conducting material having an opening throughthe outer wall thereof members, the lower end of said tube throu h whichsaid conductor and covering extend, a' sheath surrounding saiddielectric covering outside of said casing and terminating in anoutwardly bent flange at the outer wall of said casing, said flangebeing day of

